When authors research the centuries-old history between the U.S. government and American Indian tribes, use of the word "genocide" often enters the conversation. It is no stretch for any honorable human being to view the government's broken promises and forced removal of Indians as despicable.

But even the most avid amateur students of the genocidal tendencies might be unaware of what happened to the Osage tribe of Oklahoma about 100 years ago, when at least two dozen people were victims of a killing spree. David Grann, a talented New Yorker writer and author of the acclaimed The Lost City of Z, had never heard about the mysterious rash of murders, but after seeing a random reference to them, he traveled from New York City to Pawhuska, Okla., in 2012 to learn the details.

Grann discovered quickly that the genocidal behavior of the federal government had unwittingly rained wealth on Osage tribe members after they had been forced out of their Kansas settlements and onto what appeared to be worthless land in northeastern Oklahoma.

It turned out that below the surface rested huge oil deposits; those who wanted to drill had to pay the Osage tribe a quarterly royalty. Racist reports from dominant white-owned newspapers publicized the "red millionaires" and "rich redskins."

(Photo by Raymond Red Corn)

Because the wealth was no secret, white con men moved to the Pawhuska area and hatched schemes to bilk relatively uneducated Osage tribe members. One transparent technique involved white men marrying wealthy Osage women, then "legally" using the wealth as if their Osage wives never existed.

Grann decided to tell his saga of suspicious deaths within the Osage tribe by focusing on Mollie, who received oil money before marrying a white man named Ernest Burkhart in 1917. Four years later, Mollie's sister Anna was found dead away from the reservation. Grann tracks the case in detail as a prelude to other crimes. (I am wording this cautiously so I refrain from spoiling Grann's carefully crafted nonfiction mass murder mystery.)

Because tribe members were considered subhuman by the white law enforcement and court systems, it appeared that the killer (or killers) of Osage would never be identified. But as the number of bodies piled up, something surprising happened.

J. Edgar Hoover, director of the nascent FBI, heard about the Osage murders. Although a bigot, Hoover decided that an investigation might burnish his tenuous reputation and guarantee survival of the agency. So he summoned his Houston agent, Tom White, to form an investigative team to establish a command post near the Osage reservation.

White's first task would be to scrutinize the sketchy case files to determine possible links among the deaths.

White and his fellow law enforcers did not allow racial prejudice to slow their investigation. But they sensed that if they arrested any white men for murder, an assured all-white male jury would never convict them. A significant portion of Grann's narrative demonstrates how the criminal justice system rarely meant justice for nonwhites.

The final section of the book switches to first person, as Grann offers insights into how he pieced together his narrative. The vast Osage wealth had long since dissipated; Grann found poverty and depression in abundance.

But he also found Osage descendants of the murder victims who hoped to learn more about what had become a legendary "reign of terror." Examining carefully preserved documents in archives, Grann noticed details apparently unrecognized by FBI agents and trial lawyers.

His findings are summed up by a local archivist at the very end: "This land is saturated with blood," she told Grann. Then, "she repeated what God told Cain after he killed Abel." Those words, from biblical history: "The blood cries out from the ground."

Steve Weinberg is an author in Columbia, Mo., currently researching a biography of Garry Trudeau.

Killers of the Flower Moon

The Osage Murders and the Birth of the FBI

David Grann

(Doubleday, $28.95)

Plan your life

David Grann will speak at 7 p.m. April 27 at Highland Park United Methodist Church, 3300 Mockingbird Lane, Dallas, as part of Authors Live. Free; a 6 p.m. reception costs $30 (book included). Register for the reception at 214-523-2240 or hpumc.org/authorslive/.